Open/close device and electronic equipment using the device

ABSTRACT

An opening and closing device and an electronic apparatus using this device. In an urging section, a movable member including a movable cam on its side is urged by a spring. A slide member includes, at its end, a stationary cam, opposed to the movable cam, for resiliently contacting the movable cam. The movable member is urged in opening and closing directions in open and closed states, respectively according to which portion of the stationary cam resiliently contacts the movable cam. A reversing section includes a release member including a release cam resiliently contacting a support cam at the other end of the slide member, and a reversing member inserted into the slide member and including a reversing cam. When the release cam is disconnected from the support cam, the slide member slides axially, whereby the movable cam is disconnected from the stationary cam and resiliently contacts the reversing cam. The direction that urges the movable member is thus reversed, changing from the closing to opening direction.

DESCRIPTION

[0001] 1. Technical Field

[0002] The present invention relates to an opening and closing device used in an electronic apparatus such as a portable telephone or a small personal computer and also relates to the electronic apparatus using this opening and closing device.

[0003] 2. Background Art

[0004] Recently, an electronic apparatus such as a portable telephone or a small personal computer has become increasingly smaller, more lightweight and more functional. The number of so-called folding electronic apparatuses, each of which has a movable housing mounted to a stationary housing so as to able to open and close, has grown, and in these electronic apparatuses, opening and closing devices are used to facilitate the opening and closing operation.

[0005] An example of the conventional opening and closing device and the electronic apparatus using this device will be described hereinafter with reference to FIGS. 9-12.

[0006]FIG. 9 is a sectional view of the conventional opening and closing device.

[0007]FIG. 10 is an exploded perspective view of the same opening and closing device.

[0008] In FIGS. 9 and 10, cylinder 1B of movable shaft 1 is passed through central through hole 2B of movable casing 2. End 1A of movable shaft 1 is locked to stepped part 2A at a right side of movable casing 2, whereby movable shaft 1 is fixed to movable casing 2. Movable shaft 1 is made of metal, and movable casing 2 is substantially cylindrical and made of resin.

[0009] Resilient spring 3 formed of metal wire is housed in movable casing 2 in a little contracted condition. Lock part 1C of movable shaft 1 is passed through substantially elliptical through hole 4A in the center of movable member 4 made of metal, so that movable member 4 is locked to be axially movable. Movable member 4 is urged rectilinearly by spring 3.

[0010] Stationary member 6 made of metal has central through hole 6A through which a tip of cylinder 1B of movable shaft 1 is rotatably passed. Movable cam 5A of movable member 4 that provides a click feel is in resilient contact with stationary cam 7A of stationary member 6. Movable cam 5B opposite to movable cam 5A is in resilient contact with stationary cam 7B.

[0011] Movable shaft 1 is thus passed through movable casing 2, movable member 4 and stationary member 6, and C-ring 8 is fixed to lock part 1D of movable shaft 1. Opening and closing device 9 is thus formed with movable shaft 1, movable casing 2 and movable member 4 rotatably provided to stationary member 6.

[0012] Referring to FIG. 11, which includes side views, a description will be provided next of the electronic apparatus using thus-constructed opening and closing device 9.

[0013] In FIG. 11, stationary housing 25 is formed with, at its top surface, operating part 27 formed of a plurality of keys. Movable housing 26 is formed with, at its surface, display part 28 such as an LCD. Stationary housing 25 and the movable housing are formed of insulating resin.

[0014] Stationary member 6 of opening and closing device 9 is mounted to an end of stationary housing 25, while movable casing 2 is mounted to an end of movable housing 26. Movable housing 26 is rotatably supported by opening and closing device 9 so as to be able to open and close relative to stationary housing 25.

[0015] Referring to FIG. 11 and FIG. 12 including sectional views each illustrating an essential part in an operating condition, a description will be provided hereinafter of the opening and closing operation of the above-structured opening and closing device and the electronic apparatus using this device.

[0016]FIG. 11A illustrates movable housing 26 in a closed state where the surface of movable housing 26 is in contact with the top surface of stationary housing 25. In this state, movable cam 5A of movable member 4 urged by spring 3 engages with stationary cam 7A of stationary member 6, as shown in FIG. 12A, so that opening and closing device 9 is held in the closed state.

[0017] When a user swings movable housing 26 in a direction that opens movable housing 26 from the closed state against urging force of spring 3 with a hand, movable casing 2 locked to movable housing 26 causes movable cam 5A of movable member 4 to move toward slope 7C against the urging force of spring 3 through rotation.

[0018]FIG. 11B illustrates movable housing 26 in a halfway state where movable housing 26 is swung to a substantially upright position. In this state, movable casing 2 causes movable member 4 to rotate with respect to stationary member 6 of opening and closing device 9, as shown in FIG. 12B. Accordingly, movable cam 5A moves to flat part 7D of a top surface of stationary member 6 through rotation.

[0019]FIG. 11C illustrates movable housing 26 in an open state where movable housing 26 is operated to open with respect to stationary housing 25. In this state, movable cam 5B positioned opposite to movable cam 5A engages with stationary cam 7A, as shown in FIG. 12C, thus maintaining the open state.

[0020] To close movable housing 26 from this open state, the user swings movable housing 26 in a direction opposite to the direction described above, that is, in the direction that closes movable housing 26 with the hand. In this way, movable housing 26 is closed.

[0021] With the above-described conventional opening and closing device and the electronic apparatus using this device, the user can close movable housing 26 with one hand with relative ease.

[0022] To swing movable housing 26 open from the closed state, the user performs the opening operation against the urging force of spring 3. For this reason, the user, for example, holds stationary housing 25 with one hand and swings movable housing 26 open with the other hand. The opening operation is thus troublesome.

DISCLOSURE OF THE INVENTION

[0023] The present invention aims to provide an opening and closing device, which allows a user to easily perform opening and closing operation with one hand, and also aims to provide an electronic apparatus using this opening and closing device.

[0024] To achieve the above-mentioned object, the present invention has the following structure.

[0025] In the opening and closing device of this invention, a movable member is coupled to a stationary member to be rotatable in opening and closing directions.

[0026] An urging section urges the movable member in the opening direction in an open state and urges the movable member in the closing direction in a closed state.

[0027] A reversing section reverses, in the closed state, the direction the urging section urges the movable member so that the urging direction changes from the closing direction to the opening direction.

[0028] The opening and closing device of this invention further includes a movable casing, coupled to the movable member, for rotating in accordance with movement of the movable member.

[0029] In the opening and closing device of this invention, the movable casing, a spring, the movable member, a slide member, a reversing member, a release member and the stationary member are shaped into a cylinder and arranged along an axis of the cylinder.

[0030] The urging section includes the movable member and the slide member. The movable member is urged by the spring having one end pressed by the movable casing and includes a movable cam disposed along a side of the movable member. The slide member includes, at a side of one end of the slide member, a stationary cam, opposed to the movable cam, for resiliently contacting the movable cam. This slide member is disposed between the movable member and the stationary member.

[0031] The movable member is urged in the opening or closing direction according to which portion of the stationary cam is in resilient contact with the movable cam.

[0032] The reversing section includes the release member and the reversing member.

[0033] The release member includes a release cam resiliently contacting a support cam disposed on a side positioned at the other end of the slide member. This release member is disposed between the slide member and the stationary member. The reversing member is inserted into a hollow part of the slide member and includes a reversing cam.

[0034] Rotation of the release member disconnects the release cam from the support cam, whereby the slide member slides axially. Accordingly, the movable cam is disconnected from the stationary cam and comes into resilient contact with the reversing cam. Consequently, the movable member is urged in the opening direction.

[0035] In the opening and closing device of this invention, a release shaft is rotatably passed through the stationary member and connected to the release member. As the release shaft rotates, the release member is rotated accordingly, whereby the release cam is disconnected from the support cam. The opening and closing device thus rotates in the opening direction.

[0036] The electronic apparatus of this invention includes the above-mentioned opening and closing device, and its stationary housing includes at least one of an operating part and a audio input unit at its top surface. A movable housing of this electronic apparatus includes at least one of a display part and a audio output unit at its surface. The stationary member of the opening and closing device is coupled to the stationary housing, while the movable member is coupled to the movable housing.

[0037] The opening and closing device, which allows the user to open and close easily with one hand, and the electronic apparatus using this device can thus be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038]FIG. 1 is a perspective view of an essential part of an opening and closing device in accordance with an exemplary embodiment of the present invention.

[0039]FIG. 2 is an exploded perspective view of the opening and closing device in accordance with the embodiment.

[0040]FIG. 3 is a perspective view of an electronic apparatus in accordance with the embodiment.

[0041]FIGS. 4A, 4B and 4C are side views each illustrating the electronic apparatus in an operating condition in accordance with the embodiment.

[0042]FIGS. 5A, 5B, 5C and 5D are sectional developed views of an essential part for illustrating operation of the opening and closing device in accordance with the embodiment.

[0043]FIGS. 6A, 6B, 6C and 6D are sectional developed views of the essential part of the opening and closing device for illustrating operation in accordance with the embodiment.

[0044]FIG. 7 is an exploded perspective view of an essential part in accordance with another exemplary embodiment.

[0045]FIGS. 8A, 8B and 8C are sectional views of an essential part in accordance with still another exemplary embodiment.

[0046]FIG. 9 is a sectional view of a conventional opening and closing device.

[0047]FIG. 10 is an exploded perspective view of the conventional opening and closing device.

[0048]FIGS. 11A, 11B and 11C are side views of an electronic apparatus using the conventional opening and closing device.

[0049]FIGS. 12A, 12B and 12C are sectional views each illustrating an essential part of the conventional opening and closing device in an operating condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0050] An exemplary embodiment of the present invention will be demonstrated hereinafter with reference to FIGS. 1-8.

[0051] (Exemplary Embodiment)

[0052]FIG. 1 is a perspective view of an essential part of opening and closing device 30 in accordance with the exemplary embodiment of the present invention.

[0053]FIG. 2 is an exploded perspective view of the opening and closing device.

[0054] In FIGS. 1 and 2, opening and closing device 30 includes movable casing 10 and stationary member 21 and also includes spring 11, movable member 12, slide member 14, reversing member 17, release member 19, release shaft 22 and return spring 23 between movable casing 10 and stationary member 21.

[0055] For explanation, “left” or “right” is hereinafter used to indicate the direction in the drawings.

[0056] Movable casing 10 is made of resin and substantially cylindrical. This movable casing 10 has opening 10A at its left side and includes, in its outer periphery, recessed part 10B, which is shaped like an oblong hole and extends axially from opening 10A. Resilient coiled spring 11 formed of metal wire is housed in movable casing 10 in a little contracted condition.

[0057] Movable member 12 urged by spring 11 is located to the left of spring 11 to be axially movable with projection 12A, which is provided on a periphery of movable member 12, engaged in recessed part 10B of movable casing 10. This movable member 12 is made of metal and substantially cylindrical. Movable cam 13 projecting substantially in the form of a triangle is provided on a left side of movable member 12.

[0058] Slide member 14 made of metal is a substantially cylindrical slide member having a hollow part along its axis. Slide member 14 is provided with, along a border of its right side, stationary cam 15 including two slopes 15A, 15B adjacent to each other across tip 15C. Movable cam 13 of movable member 12 urged by spring 11 resiliently contacts lower slope 15A of stationary cam 15.

[0059] As described above, an urging section is formed to include above-described spring 11, movable member 12 and slide member 14.

[0060] Reversing member 17 is made of metal, substantially cylindrical and disposed inside the hollow part of slide member 14. Along a border of a right side of reversing member 17, reversing cam 18 formed with upwardly sloping slope 18A is provided in a position opposed to movable cam 13.

[0061] Reversing member 17 also includes projection 44 on its outer periphery. This projection 44 engages in recessed part 42 within the hollow part of slide member 14. Projection 44 and recessed part 42 are formed so as to allow slide member 14 to slide axially.

[0062] Release shaft 22 is substantially cylindrical, made of metal and provided with knob 22A at its left end.

[0063] Release member 19 is made of metal and includes substantially trapezoidal release cam 20 on its right side.

[0064] Substantially cylindrical stationary member 21 is made of metal and provided with, on its left side, engagement part 21A attached to a stationary housing of an electronic apparatus. Leg 46 projecting from a left side of reversing member 17 is fixed into a right side of stationary member 21.

[0065] Leg 46 of reversing member 17 is passed through hole 48 of release member 19.

[0066] Release shaft 22 is rotatably passed through central through hole 21B of stationary member 21. Release member 19 is locked to a right end of release shaft 22. This release member 19 is disposed between stationary member 21 and a combination of slide member 14 and reversing member 17 so as to be rotatable to a given angle.

[0067] Accordingly, there is a clearance between hole 48 of above-mentioned release member 19 and leg 46 of reversing member 17 for allowing release member 19 to rotate to the given angle.

[0068] Return spring 23 is a resilient torsion coil spring made of metal wire and is disposed between release member 19 and reversing member 17. Ends of return spring 23 are locked to release member 19 and reversing member 17, respectively. Spring 23 urges release member 19 in the direction of rotation.

[0069] Substantially trapezoidal support cam 16 is provided along a border of a left side of slide member 14. Urging force of spring 11 is transmitted to this support cam 16 via movable cam 13 of movable member 12 and stationary cam 15 on the right side of slide member 14. The urging force of spring 11 causes support cam 16 to resiliently contact release cam 20 of release member 19.

[0070] When release member 19 is rotated against urging force of return spring 23, release cam 20 rotates accordingly, thereby being disconnected from support cam 16. Here, slide member 14 slides axially leftward, and movable cam 13 comes into resilient contact with slope 18A of reversing cam 18, moving from slope 15A of stationary cam 15.

[0071] A reversing section is formed to include above-described reversing member 17, slide member 14, release member 19 and release shaft 22.

[0072] Between movable casing 10 and stationary member 21, spring 11, movable member 12, slide member 14, reversing member 17, release member 19, release shaft 22 and return spring 23 are arranged substantially on the same axis.

[0073] In this way, opening and closing device 30 is configured.

[0074] Referring to FIG. 3, which is a perspective view of the electronic apparatus, a description will be provided next of the electronic apparatus using opening and closing device 30 having the above structure.

[0075] In FIG. 3, the electronic apparatus includes stationary housing 31 and movable housing 32 each made of insulating resin.

[0076] Stationary housing 31 is formed with, at its top surface, operating part 33 formed of a plurality of keys, and a audio input unit such as a microphone. Movable housing 32 is formed with, at its surface, display part 34 such as an LCD, and a audio output unit such as a loudspeaker.

[0077] Stationary member 21 of opening and closing device 30 is mounted to an end of stationary housing 31, while movable casing 10 is mounted to an end of movable housing 32. Movable housing 32 is rotatably supported by opening and closing device 30 so as to be able to open and close relative to stationary housing 31.

[0078] Referring to FIG. 4 including side views each illustrating the electronic apparatus in an operating condition and FIGS. 5 and 6 including sectional developed views of an essential part for illustrating operation of opening and closing device 30, a description will be provided hereinafter of opening and closing operation of the opening and closing device having the above structure and the electronic apparatus using this device.

[0079] As mentioned earlier, movable cam 13, stationary cam 15, support cam 16, reversing cam 18 and release cam 20 are provided at a periphery of the substantially cylindrical construction in three dimensions in reality. However, these elements are shown in developed plan views in FIGS. 5 and 6 for easy understanding of operation of each element.

[0080]FIG. 4A illustrates movable housing 32 in a closed state where the surface of this movable housing 32 is in contact with the top surface of stationary housing 31.

[0081] When opening and closing 30 is in this closed state, movable cam 13 of movable member 12 urged downward as indicated by arrow F by spring 11 is in resilient contact with slope 15A of stationary cam 15, as shown in FIG. 5A. Movable member 12 is thus held by being urged rightward, that is, in a closing direction indicated by arrow G.

[0082] When a user swings movable housing 32 open with a hand, movable housing 32 and movable casing 10 rotate, whereby movable member 12 and movable cam 13 move leftward as indicated by arrow H in FIG. 5B against the rightward urging force of spring 11. Movable cam 13 thus crosses over tip 15C from slope 15A of stationary cam 15 and comes into resilient contact with slope 15B. Consequently, movable member 12 is urged leftward, that is, in an opening direction.

[0083] Then, movable cam 13 resiliently slides over slope 15B of stationary cam 15, as shown in FIG. 5C. Here, movable housing 32 shifts from a halfway state illustrated by FIG. 4B where movable housing 32 is swung to a substantially upright position relative to stationary housing 31 to a state illustrated by FIG. 4C where movable housing 32 is opened fully with respect to stationary housing 31.

[0084] In the state where movable housing 32 is opened fully, movable cam 13 resiliently contacts a left end of slope 15B of stationary cam 15, as shown in FIG. 5D. Movable housing 32 mounted with movable member 12 is thus held in a state where movable housing 32 is urged leftward, that is, in the opening direction.

[0085] When the user closes movable housing 32 with the hand from this open state, movable cam 13 resiliently slides over stationary cam 15 in reverse order, that is, in order of FIGS. 5C, 5B and 5A. In this way, movable housing 32 is closed.

[0086] A description will be provided next of a case where the user uses the reversing section instead of the hand such as described above to open movable housing 32 from the closed state.

[0087] In the state illustrated by FIG. 4A where movable housing 32 is closed, movable cam 13 of movable member 12 urged by spring 11 is in resilient contact with slope 15A of stationary cam 15, as shown in FIG. 6A.

[0088] When knob 22A of release shaft 22 is turned against the urging force of return spring 23, release member 19 locked to the right end of release shaft 22 moves rightward as indicated by arrow J in FIG. 6B. Here, release cam 20 is disconnected from support cam 16, whereby slide member 14, urged by movable cam 13, moves axially downward as indicated by arrow K.

[0089] Then, movable cam 13 moves from slope 15A of stationary cam 15 and comes into resilient contact with slope 18A of reversing cam 18. Movable cam 13 thus resiliently slides over slope 18A. Here, movable member 12 is urged leftward, that is, in the opening direction indicated by arrow H. Then movable member 12 moves in the opening direction through rotation from the state where movable member 12 is urged rightward or in the closing direction. In this way, movable housing 32 swings open.

[0090] When knob 22A of release shaft 22 is released from the turning operation, release member 19 and release cam 20 move leftward as indicated by arrow M in FIG. 6C by being urged by return spring 23. Consequently, slide member 14 is pushed up as indicated by arrow L via support cam 16, thereby returning to its original state.

[0091]FIG. 4C illustrates movable housing 32 fully opened with respect to stationary housing 31.

[0092] In this state, movable cam 13 resiliently contacts the left end of slope 15B of stationary cam 15, as shown in FIG. 6D. Movable housing 32 mounted with movable member 12 is thus held in the state where movable housing 32 is urged leftward, that is, in the opening direction.

[0093] According to the present embodiment described above, opening and closing device 30 includes the reversing section, formed of release cam 20, reversing cam 18 and others, for reversing the direction the urging section urges so that the urging direction changes from the closing direction to the opening direction.

[0094] This structure allows not only opening and closing of movable housing 32 by the user's hand but also opening of movable housing 32 through easy operation of the reversing section. Thus, the opening and closing device, which facilitates opening and closing with one hand, and the electronic apparatus using this device can be obtained.

[0095] Those elements including spring 11, movable member 12, slide member 14, reversing member 17, release member 19 and stationary member 21 that form the urging section and the reversing section are arranged on the same axis. The opening and closing device formed is thus small.

[0096] An open position and a closed position of movable housing 32 can be detected in the following manner.

[0097] For example, a variable resistor including a contact piece and a carbon electrode is formed as a detecting element between stationary member 21 and movable member 12 or movable casing 10, and the electronic apparatus is provided with a detection circuit connected to this detecting element.

[0098] The detecting element thus detects the open and closed positions of movable member 12 or movable housing 32. This realizes the apparatus including various functions. For example, display on display part 34 is blanked in the closed state and appears in the open state.

[0099] The detecting element can be a switch, an optical sensor, a magnetic sensor or the like instead of the variable resistor.

[0100] In the above description, knob 22A of release shaft 22 is turned to operate the reversing section. However, other various operations of knob 22A, including pushing, can effect the operation of the reversing section.

[0101] In the above description, axially extending recessed part 10B shaped like the oblong hole is provided in the outer periphery of movable casing 10. This recessed part 10 B engages with projection 12A of movable member 12, so that movable casing 10 and movable member 12 rotate to the same angle.

[0102] In another structure, a movable casing can be rotated to an angle larger or smaller than that of a movable member by sloping a recessed part.

[0103] In other words, as shown in FIG. 7, which is an exploded perspective view of an essential part, movable casing 29 is formed with recessed part 29B, which is shaped like an oblong hole and sloped relative to the axial direction from opening 29A. Projection 24A of movable member 24 engages in this recessed part 29B.

[0104] In this structure, movable member 24 rotates while moving axially with respect to a stationary member (not shown). Here, movable casing 29 rotates to the angle larger or smaller than the rotation angle of movable member 24 in accordance with the sloping direction.

[0105] For example, in cases where, as shown in FIG. 7, recessed part 29B is sloped in an upper-right direction from opening 29A, when movable member 24 moves leftward within movable casing 29 while rotating upward, movable casing 29, having recessed part 29B urged by projection 24A of movable member 24, rotates upward to the angle larger than the rotation angle of movable member 24.

[0106] When movable member 24 moves rightward while rotating downward, the angle of downward rotation of movable casing 29 is smaller than the rotation angle of movable member 24. A difference between these rotation angles varies, depending on an angle of inclination of recessed part 29B.

[0107] In cases where recessed part 29B is sloped in an lower-right direction from opening 29A, the relationship between the angle of upward rotation and the angle of downward rotation is reverse to the one described above.

[0108] As described above, sloping recessed part 29B of movable casing 29 with respect to the axial direction causes movable casing 29 to rotate to the angle larger or smaller than that of movable member 24 in accordance with the sloping direction when the movable member rotates while moving axially with respect to the stationary member. For this reason, a movable housing of an electronic apparatus that is mounted with this movable casing 29 can be opened and closed to a large or small angle in an arbitrary direction.

[0109] Instead of being formed into the oblong hole in the outer periphery of movable casing 10 or 29, the recessed part may be provided in the form of a groove in an inner periphery of the movable casing.

[0110] In the above description, the elements such as spring 11, movable member 12, slide member 14, reversing member 17, release member 19 and stationary member 21 are arranged on the same axis to form the urging section and the reversing section.

[0111] Alternatively, the opening and closing device may have the following structure.

[0112] As shown in FIG. 8 including sectional views of an essential part, one end of resilient coiled spring 37 formed of metal wire is held by stationary member 35 with spring 37 in a little contracted condition. The other end of spring 37 is held by movable member 36 rotatably locked to stationary member 35.

[0113]FIG. 8A illustrates movable member 36 in a closed state with respect to stationary member 35. In this state, reversing section 38 urges spring 37 to a halfway state illustrated by FIG. 8B, whereby the urging force of spring 37 that acts on movable member 36 is reversed so that the urging direction changes from the closing direction to the opening direction.

[0114] Movable member 36 is thus held in an open state, as shown in FIG. 8C by being urged in the opening direction by spring 37.

[0115] Opening and closing device 30 described above can be mounted to the electronic apparatus such as shown in FIG. 3. The electronic apparatus mentioned here includes stationary housing 31 and movable housing 32.

[0116] Stationary housing 31 is formed with at least one of the operating part and the audio input unit at its top surface. Movable housing 32 is formed with at least one of the display part and the audio output unit at its surface. The end of stationary housing 32 is mounted with the movable casing of the opening and closing device. Thus, the user can easily open and close this electronic apparatus with one hand.

[0117] Industrial Applicability

[0118] According to the present invention described above, the opening and closing device, which allows the user to easily perform opening and closing operation with one hand, and the electronic apparatus using this opening and closing device can be obtained. 

1. An opening and closing device comprising: a stationary member; a movable member coupled to the stationary member to be rotatable in opening and closing directions; an urging section for urging the movable member in the opening direction in an open state and urging the movable member in the closing direction in a closed state; and a reversing section for reversing, in the closed state, a direction that the urging section urges the movable member so that the urging direction changes from the closing direction to the opening direction.
 2. The opening and closing device of claim 1, further comprising: a movable casing, connected to the movable member, for rotating in accordance with movement of the movable member.
 3. The opening and closing device of claim 2, wherein: the movable casing, a spring, the movable member, a slide member, a reversing member, a release member and the stationary member are shaped into a cylinder and arranged along an axis of the cylinder; the urging section comprises: the movable member urged by the spring having one end pressed by the movable casing, the movable member including a movable cam disposed along a side of the movable member; and the slide member including, at one end of the slide member, a stationary cam, opposed to the movable cam, for resiliently contacting the movable cam, the slide member being disposed between the movable member and the stationary member; the movable member is urged in one of the opening and closing directions according to which portion of the stationary cam is in resilient contact with the movable cam; the reversing section comprises: the release member including a release cam resiliently contacting a support cam disposed on another end of the slide member, the release member being disposed between the slide member and the stationary member; and the reversing member inserted into a hollow part of the slide member, the reversing member including a reversing cam; and due to rotation of the release member, the release cam is disconnected from the support cam, the slide member slides axially, the movable cam is disconnected from the stationary cam and comes into resilient contact with the reversing cam, and consequently, the movable member is urged in the opening direction.
 4. The opening and closing device of claim 3, further comprising: a release shaft rotatably passed through the stationary member and connected to the release member, the rotation of the release shaft rotating the release member for disconnecting the release cam from the support cam.
 5. The opening and closing device of claim 3 or 4, wherein: (i) the stationary cam includes two slopes, the movable member is urged in the opening direction when the movable cam resiliently contacts one of the two slopes, and the movable member is urged in the closing direction when the movable cam resiliently contacts another one of the two slopes; and (ii) the reversing cam includes a slope, and the movable member is urged in the opening direction when the movable cam resiliently contacts the slope of the reversing cam.
 6. The opening and closing device of claim 1, 2, 3, 4 or 5, further comprising: a detecting element, disposed between the stationary member and the movable member, for detecting a position of the movable member relative to the stationary member.
 7. The opening and closing device of claim 1, further comprising: a movable casing including a guide part engaging with a projection provided on a periphery of the movable member, wherein the movable member and the movable casing are shaped into a cylinder, the movable member is housed in the movable casing to be movable in an axial direction, and the guide part is sloped relative to the axial direction.
 8. The opening and closing device of claim 2, 3, 4 or 5, wherein: the movable casing includes a guide part engaging with a projection provided on a periphery of the movable member; and the movable member and the movable casing are shaped into a cylinder, the movable member is housed in the movable casing to be movable in an axial direction, and the guide part is sloped relative to the axial direction.
 9. An electronic apparatus comprising: an opening and closing device of claim 1; a stationary housing including at least one of an operating part and a audio input unit at a top surface of the stationary housing; and a movable housing including at least one of a display part and a audio output unit at a surface of the movable housing, wherein the stationary member is connected to the stationary housing, and the movable member is connected to the movable housing. 